Abstract:
Under atmospheric pressure, the effects of the quinine concentration and hydrogenation temperature on the enantioselectivity and reaction rate were investigated in the asymmetric hydrogenation of ethyl pyruvate over quinine modified Pt/Al2O3 catalyst in acetic acid. The stability of the quinine modified Pt/Al2O3 catalyst and its reuse and regeneration were studied under the optimized conditions. The results show that there is an appropriate value for modifier concentration; low temperature is beneficial to the asymmetric reaction; the existence of ethyl pyruvate in reaction system can inhibit the further hydrogenation of modifier quinine. The enantioselectivity of product can increase using the Pt/Al2O3 catalyst regenerated first but decrease using the catalyst regenerated secondly.